Polymeric structures which have pores in which a given substrate can be selectively bonded are of interest in a whole series of industrial applications. In this connection, reference may be made to substance separation processes, catalytic processes or the use of these polymeric structures as sensors.
WO 93/09075 describes a process for the preparation of a polymeric structure, in which a polymer is prepared by free-radical polymerization from the monomers in the presence of a crosslinking reagent and simultaneously in the presence of a substrate. Imprinting polymers are proposed for use in chromatography, in catalysis, as biosensors or as synthetic antibodies. G. Wulff gives an overview in Angew. Chem., Int. Ed. Engl. 34 (1995) 1812-1832.
The imprinting technique, however, has a number of disadvantages. Thus the imprints show an unacceptable peak broadening and, as a rule, incomplete substance elution in the chromatographic test, the latter leading to the cross-contamination of further product fractions. Industrial application of the imprints in chromatography is thus essentially excluded. Likewise, the imprints as a rule have a low loading ability with substrate, essentially in the per thousand range, as a result of which, obviously, an only extremely small quantitative throughput can be achieved and an industrial separation process could only be carried out uneconomically.
In J. Org. Chem. 63 (1998) 7578-7579, Menger et al. describe a process in which, starting from a combinatorial mixture, polyacrylic anhydride is reacted with three or four amines selected more or less at random, 14 different amine combinations in 96 different concentration ratios leading to 1344 different polymers. The polymers were employed in the catalytic dehydrogenation of a beta-hydroxyketone, where, however, less than 1 percent of all polymers were suitable for the catalytic process at all on account of the reaction rate. In connection with the experiments, it was observed that the polymers gradually develop a better catalytic activity in the presence of the substrate. However, the polymeric structures with improved activity were not stabilized, but labile structures were obtained such that the catalytically more active structures were destroyed by changes in the pH or the temperature.